Fiber-based Infrared Heterodyne Technology for the PFI: On the possibility of breaking the noise temperature quantum limit with cross-correlation

Abstract

We present concept and first experimental lab results for a novel heterodyne correlation receiver architecture and demonstrate that it can surpass the standard quantum limit (SQL) for the noise temperature by "correlating out" the local oscillator shot noise made uncorrelated at both receivers due to replacing the laser shot noise by individual beam splitter noise. It is based on two balanced receivers, comprising in total of 4 mixers, and uses an 8-bit digitization FPGA-based 1GHz bandwidth digital correlation between the two receivers. The demonstrated prototype was built for 1550 nm using InGaAs balanced photodiodes. We present here a summary of the results described in detail in a paper accepted at IEEEAccess journal. The extra-sensitivity would lead to heterodyne being better than direct detection for wavelengths beyond 3 microns. We propose therefore this receiver architecture as a building block in a heterodyne technology to be developed for the future Planet Formation Imager Infrared Interferometer (PFI). This paper is a reduced version of a paper accepted at IEEE Access a week before the conference [1].